People in a coastal town have been advised to stay indoors following reports of a noxious odour.
Residents in Seaford, East Sussex, complained of stinging eyes and feeling sick on Friday evening.
Sussex Police issued a warning and advised people to keep doors and windows shut.
The force said one of several people to contact them about the smell described it as being “like burning plastic”.
Police are working with other agencies, including the coastguard, East Sussex Fire and Rescue Service and Lewes Council to try to determine the cause of the smell.
The odour was first noticed in The Ridings area of the town at about 6pm, and did not fade away during the evening.
In August, about 150 people were treated for breathing problems, stinging eyes and vomiting after a toxic “mist” engulfed part of the East Sussex coast.
Visitors to Birling Gap and other beaches suffered the problems when a mystery gas was blown ashore from the English Channel.
It is believed the most likely source of the fumes was a ship illegally flushing its tanks with chemicals.
Police said the smell in Seaford was not currently being linked to the August incident.